ScaffoldMessengerModifier class

Manages SnackBars and MaterialBanners for descendant Scaffolds.

This class provides APIs for showing snack bars and material banners at the bottom and top of the screen, respectively.

To display one of these notifications, obtain the ScaffoldMessengerState for the current BuildContext via ScaffoldMessenger.of and use the ScaffoldMessengerState.showSnackBar or the ScaffoldMessengerState.showMaterialBanner functions.

When the ScaffoldMessenger has nested Scaffold descendants, the ScaffoldMessenger will only present the notification to the root Scaffold of the subtree of Scaffolds. In order to show notifications for the inner, nested Scaffolds, set a new scope by instantiating a new ScaffoldMessenger in between the levels of nesting.

{@tool dartpad} Here is an example of showing a SnackBar when the user presses a button.

** See code in examples/api/lib/material/scaffold/scaffold_messenger.0.dart ** {@end-tool}

See also:

• SnackBar, which is a temporary notification typically shown near the bottom of the app using the ScaffoldMessengerState.showSnackBar method.
• MaterialBanner, which is a temporary notification typically shown at the top of the app using the ScaffoldMessengerState.showMaterialBanner method.
• debugCheckHasScaffoldMessenger, which asserts that the given context has a ScaffoldMessenger ancestor.
• Cookbook: Display a SnackBar

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• ScaffoldMessengerModifier

Available extensions

• ModifierTransformer

Constructors

ScaffoldMessengerModifier({Key? key, Key? modifierKey, Widget? child})

Creates a widget that manages SnackBars for Scaffold descendants.

const

Properties

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

final, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

inherited

buildWithChild(BuildContext context, Widget? child) → Widget

A build method that receives an extra child parameter.

override

createElement() → SingleChildStatelessElement

Create a SingleChildStatelessElement

inherited

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

modified() → Modifier

Available on Widget, provided by the ModifierTransformer extension

Transform normal widget to Modifier

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String

Returns a string representation of this node and its descendants.

inherited

toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a one-line detailed description of the object.

inherited

toStringShort() → String

A short, textual description of this widget.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited